Row-Level Security (RLS) enables customers to control access to rows in a database table based on the characteristics of the user executing a query (e.g., group membership or execution context). Row-Level Security simplifies the design and coding of security in your application. RLS enables you to implement restrictions on data row access (for example, ensuring that workers can access only those data rows that are pertinent to their department, or restricting a customer's data access to only the data relevant to their company).
Many systems do, however, share a common database connection such that a database is unaware of the particular user accessing the database. Instead, an application is used to regulate access to the data.